Incremental copying of VMs broken?

Hello, maybe I misunderstand how this is supposed to work, but I did:

incus copy incus304:ubn1 incusOSn100m: --mode=push --stateless --refresh

which copied over the VM successfully, then as a test, I deleted a text file I had on the VM, and again invoked:

incus copy incus304:ubn1 incusOSn100m: --mode=push --stateless --refresh

but received an error:

Error: Failed instance creation: Error transferring instance data: Failed migration on target: Failed creating instance on target: Failed receiving volume "ubn1": Failed to run: zfs receive -F -u local/incus/virtual-machines/ubn1.block: exit status 1 (cannot receive new filesystem stream: zfs receive -F cannot be used to destroy an encrypted filesystem or overwrite an unencrypted one with an encrypted one)

incus304 is incusOS version: 202608290126

incusn100m is incusOS version: 202609030314